NASA extends Starliner stay at space station to further assess helium leaks and thruster issues
Boeing’s leak-prone Starliner capsule will remain docked to the International Space Station for an additional four days, NASA announced Tuesday, returning to Earth with a pre-dawn landing at White Sands, New Mexico, on June 26 to close out an extended 20-day test flight — the first with astronauts aboard.
The additional docked time will give Starliner commander Barry “Butch” Wilmore and co-pilot Sunita Williams more time to help out aboard the station while flight controllers continue scrutinizing telemetry and finalizing plans for re-entry with five known helium leaks in the capsule’s propulsion system and unexpected behavior in multiple maneuvering jets.
One jet will not be used for the remainder of the flight, but the other suspect thrusters were successfully “hot fired” during a test Saturday, giving managers confidence they will work as needed to drop the Starliner out of orbit for re-entry and landing.
NASA
As for the helium leaks, engineers say the spacecraft has more than 10 times the amount needed for the remainder of the flight. During the hot-fire test on Saturday, the leak rates were less than what telemetry indicated earlier in the mission, but engineers are still assessing data to better understand the behavior of the system.
launched June 5, a month later than planned due to problems with its Atlas 5 rocket, trouble with a countdown computer and an initial helium leak in the system used to pressurize the capsule’s thrusters.
NASA and Boeing managers decided the leak was too small to pose a safety threat and the ship was cleared for launch. Once in orbit and on the way to the space station, however, four more helium leaks developed and the Starliner’s flight computer took seven maneuvering jets offline when the telemetry did not match pre-launch expectations.
Stich said the hot-fire test Saturday showed the jets needed for post-undocking maneuvers and the critical de-orbit “burn” will work as needed to take the ship out of orbit for re-entry. Likewise, he said engineers were confident the helium leaks can be managed even if one or more gets worse after undocking.
But the additional days docked with the space station will give engineers more time to review data and monitor telemetry from the Starliner’s service module, which is where the thrusters and the helium pressurization plumbing are located. Engineers will not be able to study the actual hardware because the service module is discarded prior to re-entry and will burn up in the atmosphere.
“We’re taking extra time given that this is a crewed vehicle, we want to make sure that we haven’t left any stone unturned,” Stich said. “We also want to look at the systems and potential interaction between the systems and make sure we haven’t missed something before we return.”
“I like the fact that the vehicle is staying a little longer,” he added. “I like the fact that we’re watching how the vehicle performs thermally, how the space station charges the batteries. We’re getting to see those kinds of cycles, which we absolutely need for the subsequent missions. … So I think there’s a silver lining in staying a little (longer at the space station).”
Before launch, NASA managers had hoped the Starliner test flight would pave the way toward certifying the spacecraft for operational space station crew rotation missions starting early next year. But given the problems encountered earlier in the flight, certification could be delayed depending on what is required to address the issues identified to date.
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Source: cbsnews.com